1. Field of the Invention
The invention relates to a chain for a chain-type continuously variable transmission and, more particularly, to the structure of the chain.
2. Description of Related Art
There is a continuously variable transmission including two pulleys and a flexible endless member. The two pulleys each have a pair of facing conical surfaces that are able to change a distance therebetween. The flexible endless member is wound to span between the two pulleys. Rotation of one of the pulleys is transmitted to the other one of the pulleys by the flexible endless member. At this time, the radius of the flexible endless member wound on each pulley is changed by changing the distance between the corresponding conical surfaces, so it is possible to change a speed ratio. A chain (plate link chain) that is used as the flexible endless member of the continuously variable transmission is described in Japanese Patent No. 4821022.
The chain is configured such that links (plates 39, 40) arranged in a circumferential direction of the chain are coupled to each other by pins (pivotal pieces 32, 33) extending through these links. End faces of each pin contact the conical surfaces of each pulley, and each pin is sandwiched by each facing pair of sheaves. The shape of each end face of each pin, which contacts each sheave, is a circular arc in a plane perpendicular to the circumferential direction of the chain (see paragraph 0023, and the like). By forming each pin end face into a circular arc shape, an impact at the time when the pin grips each pulley is reduced.